A. Field of the Invention
The present disclosure relates generally to the field of altering and/or generating currents in biological tissue for the purpose of stimulation. More particularly, the present disclosure relates to an apparatus that serves as an interface mechanism between tissue being stimulated and/or an electrical field (and/or electric field source) and/or a means for altering the tissue electromagnetic parameters (fields, agents, and/or sources).
B. Background Information
Electric stimulation of living tissue in humans and other animals is used in a number of clinical applications as well as in general biological research. In particular, electric stimulation of neural tissue has been used in the treatment of various diseases including Parkinson's disease, depression, and intractable pain. Focused and/or deep stimulation of the brain usually involves performing surgery to remove a portion of the skull and implanting electrodes in a specific location within the brain tissue. The invasive nature of these procedures makes them difficult and costly, and is responsible for a great deal of morbidity. Alternately, noninvasive stimulation methodologies such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) are easy to implement and are not associated with significant morbidity, however, the areas stimulated are large, typically not well characterized, and can be significantly perturbed by natural or pathological features of the brain tissue. Recently, ultrasound stimulation of brain tissue has been explored with limited success, as it alone does not generate currents that are the backbone of clinically effective stimulation methods.
Numerous methods exist for generating currents for biological tissue stimulation. These methods range from implanting electric sources in the tissue to inductively generating currents in tissue via time-varying magnetic fields. A new method for generating currents in biological tissue was recently described in U.S. patent application Ser. No. 11/764,468, Apparatus and Method for Stimulation of Biological Tissue, which discloses an apparatus and method of generating currents in biological tissues. The disclosure describes a means to stimulate biological tissue via an electric source capable of generating an electric field across a region of tissue and a means for altering the electromagnetic properties of tissue relative to the electric field, whereby the alteration of the tissue electromagnetic properties relative to the electric field generates an altered current in the tissue. These alterations in the current in turn lead to the stimulation of biological tissue. The means for altering these electromagnetic parameters of the tissue could include a chemical, optical, mechanical, thermal, and/or secondary electromagnetic source(s), field(s), and/or agents.
Presently, no apparatus exists which can improve on the interface between the primary electric source (and/or field) and/or means to alter tissue electromagnetic properties (source(s), field(s), and/or agents) and/or the tissue(s) to be stimulated for this type of tissue stimulation method. No interface exists which can regulate the number of and/or duration of stimulation sessions. No interface exists which can control, move, and/or fix the location and/or sizes of the source of the primary electric field and/or means for altering the electromagnetic properties of the tissue(s) to be stimulated for this type of tissue stimulation method. No interface exists Which specifically bridges, couples, and/or matches the properties of the materials between the primary electrical field source (and/or its field) and/or the source of the means for altering these electromagnetic parameters of the tissue (and/or the fields and/or agents) and/or the tissue in such a way to improve stimulation for this type of tissue stimulation method. No interface has been proposed which can be worn, integrated with wearable items, house any of the sources of stimulation, and/or serve as a bridge between tissue(s) to be stimulated and any of the sources of stimulation.
It would be desirable to provide an interface mechanism between the stimulated tissue and/or the source electrical field(s) and/or the means for altering the tissue's electromagnetic characteristics that makes such improvements. The present disclosure addresses these deficiencies.